How to connect to wifi in Ubuntu Server 20.04?

Question

ubuntu

Hello! There was a problem with Nvidia drivers after installing Ubuntu Server 20.04.1 on an old (i5-3210) laptop, using nomodeset booted and entered the console. Next, you need to connect to Wi-Fi (no wire, only wi-fi) from the command line.

Several methods found did not help, because. the following commands do not work (command not found, packages are not installed, but I can't download them without the Internet):
nmcli
wpa_supplicant
dhcpcd
ifup/ifdown

Answer 1

So netplan is now in charge of the whole thing in Ubuntu.
Konifg in /etc/netplan
Or 01-netcfg.yaml
Or 01-network-manager-all.yaml
All parameters are registered in them.
By default, in the first such command:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd

As a rule, in a system without DE.
In the second one like this:

# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager

As a rule, it is generated after installing the DE, to work with NetworkManager.
But there are many parameters that are prescribed and manually, if desired, if the default does not work.
You can find a lot of instructions in the open spaces ...
After editing the config, you must follow:
sudo netplan apply
to activate the changes.
Well, you can also execute before that:
sudo netplan try
to check for errors and if there are none, then the first command.